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SECCHI Sun Earth Connection Coronal and Heliospheric Investigation

SECCHI Sun Earth Connection Coronal and Heliospheric Investigation. R.A. Howard Presentation to Stereo SWG#1 27,28 January 2000 Web Site: http://secchi.pxi.com. Outline. Science Description Modeling E/PO Instrument Description Accommodation Concerns. CME INITIATION.

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SECCHI Sun Earth Connection Coronal and Heliospheric Investigation

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  1. SECCHISun Earth Connection Coronal and Heliospheric Investigation R.A. Howard Presentation to Stereo SWG#1 27,28 January 2000 Web Site: http://secchi.pxi.com

  2. Outline • Science Description • Modeling • E/PO • Instrument Description • Accommodation • Concerns

  3. CME INITIATION

  4. EXAMPLE OF STEREO CME ANALYSIS Tie Line

  5. SECCHI Observables

  6. SECCHI MHD Modelling • Necessary to help interpret SECCHI observations and to connect them to the in-situ and radio observations • 3 broad MHD objectives • Model the quasi-static plasma parameters • Investigate the physics of the initiation of CMEs • Propagate a transient structure into the heliosphere • Other groups can use these model outputs as boundary values to modules to predict solar wind properties, energetic particles and radio emission. • Must be ready at the time of launch!

  7. SECCHI Data and Analysis Tools • Available to the community at launch • Calibration tracking tool • Removal of energetic particle tracks • Structure measurements • Movie tool • Potential B field tool • Emission measure map tool • Image visualization tools (single/multiple instrument) • Three-dimensional image reconstruction • CME propagation modeling tool

  8. SECCHI Data Archive • DVD Disks • Double Sided Double Density => 17 Gbytes capacity • Containing data from both S/C for 2 days • Will include • SECCHI Data • Steady State Model • Propose to include other Stereo instruments • Distribution • To all Co-I institutions • NASA SDAC

  9. Guest Investigator Program • SECCHI has included funding (~$2M) in its budget for a GI program • Administered by NASA • Supplement to the normal NASA GI program • Would start 1 year before launch

  10. SECCHI Education & Public Outreach • Develop web pages • Develop Master teacher workshops and self-contained educational toolkits, educational CD-ROM • Develop Stereo component of SUNBEAMS • Support 1 teacher/year to work with SECCHI scientist • Develop “low-tech” planetarium show on Sun and space weather • Produce SECCHI images and animations for E/PO • Maintain interactive programs with K-12 schools

  11. SECCHI Mass, Size, Power

  12. SECCHI Instrument Heritage

  13. EUVI Bandpass Mask Filter Wheel Shutter Door COR1 Rotating wave plate Shutter Door COR2 Rotating wave plate Shutter Door HI Shutter Door SECCHI Mechanisms

  14. HI-1 (Red) and HI-2 (Blue) Fields of View

  15. Stray/Zodiacal Light Model Subtraction LASCO/C3 Coronal Image Taken on 20 June 1999: The Left Panel Shows the Typical Football Shaped Distribution of the Zodiacal Light (F-corona) That Overlies the Dimmer K-corona at Moderate and Long Elongations From the Sun. In the Right Panel, the Zodiacal Light and the Stray Light Have Been Removed to Show Clearly the Background Stars, Coronal Streamers and a CME in Progress in the North East.

  16. Heliospheric Imager (HI) Instrument ParametersConcept Diagram HI-1 (Red), HI-2 (Blue)

  17. Coronagraph 2 (COR2) Instrument Parameters Resolution Vignetting COR2 Optical Layout

  18. Coronagraph 1 (COR1) Instrument Parameters Vignetting Axial Color From the Singlet Object Leads to Vignetting at the Occulter. The Vignetting Has a Chromatic Character Inside of 1.3 R0. COR1 Field Lens/Occulter Detail COR1 Optical Layout

  19. Vector Magnetograph and Guide (VMAG) Scope Instrument Parameters Transmission Profile of Magnetograph Fabry-Perot VMAG Optical Elements VMAG Optical Layout

  20. Extreme Ultraviolet Imager (EUVI) Instrument Parameters EUVI Effective Layout EUVI Temperature Response EUVI Optical Layout

  21. SCIP Composite Optical Box Low-Outgassing GrCE Composite Material Detailed Optical Box Design Reduces Development Risk High Fidelity FEM Model Shows Primary Mode (149 Hz)

  22. Measurements of the Quantum Efficiency of a UV Enhanced CCD No Anti-Reflection Coating is Used on the EUVI Detector

  23. SECCHI ORGANIZATION

  24. SECCHI INTEGRATION FLOW

  25. SECCHI Concerns/Uncertainties • Pointing • Stability • Clear field of view • Alignment • Co-alignment to be checked before/after vibration • Coronagraph internal alignment to be checked before/after vibration • Mass, size • Proposal was constrained to meet the perceived Pre-phase A S/C • There are trade-offs we can make if there is some flexibility here, eg. Square off the SCIP box, Composite to Aluminum • Power • Power seems to be the major S/C constraint • Concern about the amount of heater power that might be necessary

  26. SECCHI Pointing/Alignment Requirements

  27. SECCHI Accommodation Concerns (Contd) • Telemetry • In order to do a pB sequence before a CME has moved across a COR1 pixel, the SECCHI telescopes are capable of very fast operation, removing a major design limitation of the SOHO LASCO/EIT. • SECCHI is very flexible in its internal TM allocation among the various telescopes • There are times when an extremely high cadence is required • A variable daily data volume could be implemented as the S/C separate from Earth

  28. Example of fast evolution from TRACE. Significant changes even with a 1 minute cadence Note jet in upper left and changes to active region

  29. SECCHI Telemetry Options

  30. SECCHI Accommodation Concerns (Contd) • Contamination • Extremely sensitive to particulate and molecular contamination at apertures • Dry Nitrogen Purge for SCIP • Contamination needs to be addressed at the design phase • Witness plates to be examined after major system tests • Only open the coronagraph doors in Class 100 • Cannot accept thruster gas over the apertures => may need to add doors that can be cycled => mass and power • GuideScope and EUVI don’t need • HI, COR1, COR2 TBD

  31. SECCHI Accommodation Concerns (Contd) • Thermal issues • Concept for thermal radiators for CCD cameras (-60 C) • Power for CCD heaters during initial operations and whenever instrument is off • Non-op heater power for HI, SCIP and SEB • Location of SEB => collective thermal control • I&T • Stimuli get put in front of the apertures during some tests • Alignment/co-alignment activities • Witness plate replacement • Will utilize a test connector when on the S/C • Final “button-up” activity as late as possible

  32. SECCHI Concerns (Contd) • Parts program • GSFC could be a big help • Availability of high reliability parts e.g. CPU, 14/16 bit ADC, etc • Schedule, Funding • We want the mission to succeed (eg not to exceed cost cap), but ... • startup delayed 4 months from AO/Proposal dates => shrinkage in overall schedule from what we proposed • $$ not matching schedule => inefficiency in our program => delays

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